1. Field of the Invention
The present invention relates to a pump arranged to transfer a fluid through a pressure generated by a dynamic pressure groove.
2. Description of the Related Art
In recent years, electronic components containing CPUs or the like have been reduced in size, and an increase in the amount of arithmetic processing has increased the amount of heat generated by the electronic components. One method of cooling such an electronic component is to load a refrigerant liquid in a heat pipe, and cause the refrigerant liquid to circulate in the heat pipe to cool the electronic component. For efficient cooling of the electronic component, use of a pump to cause circulation of the refrigerant liquid is effective. Miniaturization of the electronic components demands miniaturization of pumps.
A known small-sized pump is described in, for example, JP-A 2007-218154. The known small-sized pump described in JP-A 2007-218154 is a vortex pump including: an impeller including a disc-shaped blade portion including a plurality of blades at an outer circumference thereof, and a tubular bearing portion including a bearing at an inner circumference thereof; a shaft arranged to support the impeller such that the impeller is movable in a thrust direction; a drive apparatus arranged around the bearing portion of the impeller to rotate the impeller; and a case member arranged to contain the impeller, the shaft, and the drive apparatus. The case member includes a fluid transfer portion arranged to accommodate the blade portion, and a drive apparatus accommodating portion arranged to accommodate the drive apparatus. Dynamic pressure grooves arranged to generate dynamic pressures in accordance with rotation of the impeller are defined in both faces of the impeller or in surfaces of the case member which are opposed to the respective faces of the impeller. The dynamic pressure grooves are defined at positions inside of the blades.
The impeller of the known pump includes the blade portion including the plurality of blades, which are arranged to transfer a fluid, and the tubular bearing portion including the bearing at the inner circumference thereof. The known pump needs to include a space to accommodate the blade portion, which makes it difficult to further reduce the size of the electronic component.